From F. Scott Fitzgerald's "The Last of the Belles" in the Saturday Evening Post - March 2, 1929.
Spurs are used to make a horse go faster. (I don't use them on horses myself.)
This is an analogy used to compare the above situation with a horse rider using something to cause forward motion.
Something (I can't tell what, from this passage) was used to move his airplane forward.
I am really not sure!
I wonder if it is referring to the bars on a uniform, indicating his piloting skills?
Well, after I posted, I saw the other two responses. They obviously understood it as literal, rather than analogous. The writer included a joke, and I didn't catch it. LOL